void setup() {
  // put your setup code here, to run once:
  pinMode(4,OUTPUT);
   pinMode(5,OUTPUT);
    pinMode(6,OUTPUT);
     pinMode(7,OUTPUT);
     Serial.begin(9600);
     
}

void loop() {
  // put your main code here, to run repeatedly:
  digitalWrite(6,LOW);
  digitalWrite(7,HIGH);
  delay(5000);
  digitalWrite(6,HIGH);
  digitalWrite(7,LOW);
  delay(5000);
}
